Re: Reduced power consumption in autovacuum launcher process

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Mon, Jul 18, 2011 at 9:12 AM, Peter Geoghegan <peter(at)2ndquadrant(dot)com> wrote:
>> There could perhaps be a very large "nap", as determined by
>> launcher_determine_sleep(), so that the total number of microseconds
>> passed to WaitLatch() would exceed the maximum long size that can be
>> safely represented on some or all platforms. On most 32-bit machines,
>> sizeof(long) == sizeof(int), which is just 4 bytes. (2^31) - 1 =
>> 2,147,483,647 microseconds = only about 35 minutes. There are corner
>> cases, such as if someone were to set autovacuum_naptime to something
>> silly.

> OK. In that case, my feeling is "yes, you need to worry about that".
> I'm not sure exactly what the best solution is: we could either
> twiddle the WaitLatch interface some more, or restrict
> autovacuum_naptime to at most 30 minutes, or maybe there's some other
> option.

A wakeup once every half hour would surely not be an issue from a power
consumption standpoint. However, I'm not sure I understand here: aren't
we trying to remove the timeouts completely?

regards, tom lane